The present invention relates to control devices and methods for controlling an electric power supply system of a fuel cell powered vehicle and, more particularly, to a control device and method for a fuel cell powered vehicle that alleviates a sense of discomfort in acceleration feelings encountered during a drop in an air density such as in traveling in high altitudes.
As countermeasures to address environmental issues in recent years, particularly, global warming issues resulting from air pollutions and carbon dioxide emissions due to automotive exhaust gases, fuel cell technologies have been focused on because these technologies enable clean emissions and the realization of high-energy efficiencies. Therefore, at the present days, there have been increasing efforts in research and development work related to fuel cell powered vehicles on which such a fuel cell is installed as a main power supply.
In cases where the fuel cell powered vehicles travels in high altitudes and then an air density drops, difficulties are encountered in supplying reaction gas (oxidizer gas) at a desired pressure and flow rate and electric power generated by a fuel cell becomes unstable causing an electric current to be extracted with electric power being generated under a shortage of reaction gas to be supplied, resulting in issues of performance degradation of the fuel cell.
Therefore, Japanese Patent Applications No. 2002-352826 and No. 2002-352833 propose control technologies, for a fuel cell operating under circumstances with a drop in an air density such as traveling in high altitudes, in which an atmospheric pressure is detected and the rotational speed of a compressor is corrected so as to obtain oxidizer gas at a desired flow rate for a demanded electric power output whereupon the fuel cell is operated to generate electric power.